Immunology

NK Cells all in a Row

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Science  05 Oct 2001:
Vol. 294, Issue 5540, pp. 15
DOI: 10.1126/science.294.5540.15b

Natural killer (NK) cells are functionally distinct in their responses to viruses and tumors and in immune regulation. Hence, they have been proposed to mature in a bifurcated fashion analogous to that of type-1 and type-2 T helper cells, which are classified by the profile of cytokines they produce.

Loza and Perussia set out to test the idea that NK cells and T helper cells follow a similar course of differentiation in the acquisition of type-1 or type-2 characteristics. Immature NK cells were isolated from human blood and cultured in the presence of cytokines known to induce either a type-1 or type-2 phenotype. Cell fate was then tracked by using expression of the type-2 cytokine interleukin 13 (IL-13) and the type-1 cytokine interferon γ (IFNγ) as markers for differentiation. The cytokine IL-4 promoted proliferation of NK precursors into immature type-2 (IL-13) NK cells but did not support their development into an intermediate type-0 (IL-13/IFNγ) cell. Instead, this transition was induced by IL-12, which caused these intermediary cells to cease production of IL-13 and to progress to fully functional type-1 (IFNγ) NK cells. Thus, all three phenotypes of NK cell may be related by a linear pathway of differentiation.—SJS

Nature Immunol.2, 917 (2001).

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